Tyrosine codon 1070 (TAT) was changed to phenylalanine (TTC) (p.Y1070F) through an AT>TC mutation in exon 14 or 15 (depending on splice variant) using an sgRNA (targeting TCCACGCATACTGTCACCTA) and ssODN template (ATCTCCACGCATACTGTCACCTTCGGCAAC) with CRISPR/Cas9 technology. This mutation prevents phosphorylation of the residue. (J:334279)